Engineering Lignocellulose Fibers with Higher Thermal Stability through Natural Fiber Welding

This study reveals how natural fiber welding (NFW) can be used to engineer biopolymer materials with improved thermal stability. First, it is shown how NFW without binders improves lignocellulose yarn thermal stability by ≈17 °C, primarily by condensing microfibril structure. Next, silanized‐cellulose nanofibrils (Si‐CNFs) are developed as NFW binders; this silanization process alters CNF physical and thermal properties. During pyrolysis, Si_x O_y networks form, which delay CNF decomposition (up to 37 °C), slow cellulose mass loss rates (up to 89%), and can enhance char yield more than twofold. When used as NFW binders, Si‐CNFs increase lignocellulose yarn thermal stability (up to 17 °C) proportional to siloxane amount, and can reduce cellulose mass loss rates (≈25% compared to welding without binder). These exciting results highlight the potential of NFW as a green‐engineering process to transform natural fibers into more thermally stable, biocomposite textile yarns.